The “transmission” in the Accord Hybrid is a typical example of Honda’s practice of elegant engineering – developing simple solutions to complex problems.

Unlike the complex systems used by most hybrids, where a Continuously Variable Transmission (CVT) is combined with electric motors, the Accord hybrid uses two electric motors to serve the purpose of a transmission.

The main 166-horsepower, 6.7 kWh electric motor provides motivation from rest to top speed. With maximum torque (226 lb-ft) available from idle it gets the car underway with silent authority.

At speed, however, (from 70 km/h), the electric motor's performance is not as impressive so a second electric motor brings the gasoline engine up to speed and a clutch is engaged connecting it to the front drive wheels.

The two (motor and engine) work together from that point, with rpm changing with road speed.

In addition to acting as a starter, the smaller secondary electric motor is busy at other times. When the driver’s foot comes off the throttle and/or applies the brakes, it acts as a generator, putting power back into the big battery.

Honda says this design has half as much friction as a conventional transmission.

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December 18, 2013

The 2014 Honda Accord hybrid may look like its siblings, but it stands apart because of a unique and highly effective approach to the whole issue of hybrids. It is a perfect example of what Honda is know for, elegant engineering – providing a simple solution to a complex problem.

The result is a roomy, luxurious and quiet mid-size sedan with micro-car fuel economy and no transmission – more on this in a minute.

The ninth-generation Accord came to market last year and my fellow AJAC members voted it Canadian Car Of The Year. It was followed by a plug-in hybrid later in the year.

Now, Honda has added the non-plug-in Hybrid to the Accord family for 2014 and it is a complete rethink of the hybrid process operating under the umbrella of i-MMD (Intelligent Multi-Mode Drive).

In typical hybrid fashion it uses a combination of electric and internal combustion motivation. But with a twist.

i-MMD

The i-MMD system incorporates two electric motors, two control units and a high-output 1.3 kWh lithium-ion battery. The large motor, producing 226 lb-ft of torque from rest, uses power from the lithium-ion battery pack to drive the wheels, changing speed as necessary. The smaller motor serves as a generator to supply power to the battery pack.

The IC (internal combustion) engine is a 2.0-litre four-cylinder operating on the Atkinson Cycle – by which the intake valves close later than in conventional engines – sacrificing some power in return for cleaner combustion and lower fuel consumption. Its rated output is 141 horsepower.

That slight decrease in power is offset by that from the electric motor which delivers maximum torque from idle and 166-horsepower at peak.The combined output of the two is 196-horsepower.You can’t simply add the two numbers together because they reach peak power at different times.

The Accord hybrid accelerates to 100 km/h two-tenths of a second sooner than the conventional four-cylinder Accord.

It's a typical hybrid to this point. But there are numerous other tricks to this engine, including a two-mode variable valve-timing system and electrically-operated air-conditioning, cabin heater and brake booster.

No transmission

The most significant difference between the Accord Hybrid and other hybrids is the lack of a conventional transmission. See sidebar.

The Accord Hybrid operates in three modes:

1) pure electric, in which energy from battery powers the car;

2) hybrid, engine on and powering the generator which drives the electric motor and wheels with assistance from the battery pack; and

3) engine only – at highway speeds.

Most of the time the Accord Hybrid is in hybrid drive with both engine and motor at work. Engine speed changes according to input from the controller, not the throttle, to keep it operating within its most efficient speed range.

The Accord Hybrid starts in electric mode. The control unit selects which of the three – EV, hybrid or engine – modes the vehicle is in and continually pushes for electric operation. Where others lurch between electric and hybrid drive modes, the Accord’s operation and transitions are seamless.

There is an aptly-named green “EV” button that forces pure electric operation as long as there is sufficient battery power.

It all works impressively well, giving the Accord Hybrid the best fuel consumtion ratings of any vehicle in its class.

Electric Servo Brake

The Accord’s Electric Servo Brake is used to not only to slow the car, but to regenerate electricity – just like other hybrids. But in this case it does so seamlessly, without the abrupt grab felt in other systems as the regeneration and braking functions join forces.

It utilizes a “Pedal Feel Simulator” attached to the pedal assembly, to maximize energy capture while providing good brake feel. This proprietary design was first utilized on the Fit Hybrid sold in the U.S.

Upon initial and under light pedal application (up to 0.2 G) the regenerative braking system slows the car while capturing energy. It feels like a normal brake. With more pressure, the hydraulics kick in and conventional friction braking comes into play. That transition is all but impossible to detect.

Accord to the core

Other than the drive and braking systems, the 2014 Accord Hybrid is essentially the same as other Accord sedans. All dimensions are the same except for the trunk which drops in capacity from 450 to 360 litres because of the battery pack, which also precludes lowering the rear seat back for more room.

The extra weight of the battery pack and electric motors is offset by the use of aluminum instead of steel for the hood, rear bumper supports and some suspension components.

From the outside you can tell the hybrid apart from other Accord by unique wheels, a tiny rear lip spoiler and blue trim accents around the grille, head and tail lights.

Inside, the instrument panel is unique with a large central speedometer flanked by a bar chart on the left displaying power delivery and on the right fuel and battery charge levels are visible. The centre of the speedometer is used to display various secondary pieces of information.

This hybrid does not sacrifice dynamics for efficiency. Special shock absorbers are used that provide a softer ride at low speed and stiffen up when pushed in the turns. Despite low rolling resistance tires there is a degree of alacrity not associated with vehicles whose primary purpose is to save fuel.

The Accord Hybrid comes in two trim levels, base and Touring at prices $6,000 above the corresponding base and V-6 Touring models. In addition to the fuel-saving hybrid drivetrain both have a raft of additional standard equipment when compared to their counterparts.